VentilationVentilare – to be exposed by the wind

Main purpose• Removal of pollutants

– Gas– Particles– Too much heat

• Create a good indoor climate– No draught– Small temperature differences in the

occupied zone

VentilationAn effective ventilation is needed to thin pollutants and to remove the polluted / used air from the building and supply as clean air as possible.

In some cases the incoming air needs to be cleaned before it is used as supply air.

A light under pressure in the building can avoid internal moisture to be pressed out in the construction.

Deliberated ventilation + involuntary ventilation = total ventilation.

Definitions

• Airflow qin l/s, m3/s or m3/h

• Specific airflow n (airchange rate)in arch (oms/h) n = q / V n = number of room volumes / hWhere q = air flow in m3/h

V = room volume in m3

The indoor climate is a combination of the four technical climates;

• Air hygiene• Thermal climate• Acoustics climate• Visual climate

Thermal comfort

• The limits for private nuisance for indoor air temperature is below 18°C or above 28 °C.

• A good indoor comfort temperature interval is between 20 °C och 24 °C

How to keep a good indoor climate?

• Stable against disturbance– Outer (wind and temperature)– Inner (convection from heating sources)

• Easy to control and measure– Plan the ventilation to be easy to reach!

The building regulations concern the occupied zone

Swedish Building RegulationsBBR

Thermal comfort

Ventilation - planning

Ventilation - air distribution

Recommended air flows• Bedroom –

minimum supply air of 4 l/s, sleepingplace

• Kitchen and bathroom with windows –minimum exhaust air flow of 10 l/s

The airflows in the buildings must be in balance!

Occupied zone

The volume is limited by planes, parallel to the walls, ceiling and floor of the room.

Occupied zone

Principles of ventilation

• Mixed flow ventilation (mekanisk ventilation)

• Displacement flow ventilation (deplacerande ventilation)

Mixed flow ventilation

• Can be used for comfort ventilation, both for heating and cooling

• The concentration of pollutants are the same in all parts of the room

• Is normally supplied in the level of the ceiling or under windows

Mixed flow ventilation– placementof supply air devices

Rear edge deviceDevice close to radiator

Displacement flow ventilation

• Supply air is let in close to the floor with a low velocity

• Exhaust air is sucked out at the level of the ceiling

• The air current is thermally directed

Near zone

Displacementflow devices- placement

A1 Extract air

U1 Outdoor air

FD Exhaust air device

TD Supply air device

ÖD Transfer units

YG Outerwall grill

LD Silencer

EI60 Border of firecell

BSPJ Commissioningdamper

SPJ Damper

T1-125-2Supply air duct type 1

DimensionInsulation type 2

Units

Exhaust air

Supply air

Extract air

Outdoor air

Supply air devices

Ceiling air diffusers

Wall air diffusers

Wall air terminal devices

Low velocity terminal

Exhaust air device

Transfer units

Silencers

Residential ventilation

Good ventilation is important for both our health and the health of the building

Insufficient and inadequateventilation can be discovered as

• Condensation on the internal glasspaneduring winter.

• A feeling of stuffy, ”heavy”, air.• Bad catching of smell of frying.• Lasting condensation on bathroom mirrors

after showers and baths.

The cause of the problems with the ventialtion can be

• A bad functioning natural ventilation, especially during summer

• An idle exhaust fan• Dirty filters• Dirty ducts• Not enough supply air

Residential ventilation - history

• Before 1970Houses built before 1970 is mostly not air tight

and the ventilation is handled by draught The air exchange rate is mostly low, especially

in the summer when the temperature difference between outside and inside is marginal. This temperature difference is the driving force for the air change rate.

Residential ventilation - history

• During the 70´s During the 70´s the houses were built more air tight to save energy. In many cases nothing was done with the ventilation system and have caused problems with a bad indoor climate and moisture problems.

Residential ventilation - history

• In the 80sBuildings produced during the 80s has mostly a mechanical ventilation system.

Residential ventilation – technique

• Natural ventilation• Mechanical ventilation

– Electrical power for fans needed– F (exhaust air ventilation), FT (supply- and

exhaust air ventilation) and FTX (supply-and exhaust air system with heat exchanger)

• Hybrid ventilation

Residential ventilation – technique

• Natural ventilation– In buildings with natural ventilation there is no

mechanical fan. The air is let in by leakages and planned air slits and is exhaust in exhaust air pipes, often placed in the chimney stack.

• The chimney stack is the heart of the house

• Be carful when adding thermalinsulation– Air tightness increases,

less supply air

Natural ventilation

• Increased natural ventilation

You can increase the natural ventilation with a fan that is controlled by the outdoor temperature.

• Plus– Quiet– No need of electricity

Natural ventilation

• Minus– Risk of bad ventilation– Risk of draught– Can not re-use the heat

in the exhaust air

Exhaust air ventilation

In the exhaust air ventilation system a mechanical fan is always running, creating a underpressure in the house.

Exhaust air ventilation

• Supply air by outdoor air intake

Exhaust air ventilation

• Plus– Can re-use the heat in the exhaust air– Can filter the supply air

• Minus– Electricity needed for fans– Risk of noise

Hybrid ventilation

• A mix between natural ventilation and mechanical supply air system– Fans are installed to support the natural ventilation

system to keep a invariable supply air flow – Suitable where you have a surplus of heat and a

low need of heat exchange, like a classroom– Complicated to adjust

Mechanical ventilation

• A balanced ventilation – air flows in and out from the building are equal

Supply and exhaust ventilation with heat exchanger (FTX-system)

Nr. 1. Supply airNr. 2. The cold supply air is heated in a heat exchanger by the warm exhaust air. Nr. 3. Heated supply air is let in to the house. Nr. 4. The used exhaust air is taken out from the kitchen and bathroom. Nr. 5. The exhaust air is getting cold in the heat exchanger and is let out.

FTX• Plus

– Can supply much air– Works in all weather conditions – Energy effective

• Minus– Risk of noise– Needs maintenance –

sensitive for pollution

Outdoor air heat pump

The outdoor air heat pump extracts heat from the outdoor air and carry the heat to the waterborne system in the house, for both heating the house and for domestic hot water.

Comfort heatpump/air-to-air heat pump

The air-to-air heat pump extracts heat from the outdoor air. The indoor part is placed central in the house to make sure the heated air is distributed in a good way.

Exhaust air pump

The exhaust air pump gets heat from the exhaust air in the ventilation system, so to be able to use this kind of heating system the building needs a regulated ventilation system.

The exhaust air pump can be connected to the waterborne heating system or/and be used for domestic hot water.

Exhaust air pump1. A fan in the heat pump collects the heated exhaust air.

2. The exhaust air is heating the cooling media that evaporates.

3. In the compressor, the temperature of the cooling medium is greatly increased.

4. The heat is emitted in a condenser to the buildings heating and hot water system.

5. The pressure of the cooling medium is decreased and turns back to liquid form.

6. The liquid cooling medium returns to the compressor.

Bokliden – Sveriges första äldreboende med passivhusstandard!

• Highly insulated, airtight climate shell• Moderate window area, windows with low U-value• FTX-system with one central unit• Small radiator in each room for additional heat

Model of app. in one corner

Peak load for space heating:23°C 19 W/m²20°C 16 W/m²

Energy needed for heating:23°C 26 kWh/m²,år20°C 14 kWh/m²,år

Well insulated climate shell

Installation layer

Insulated on roof to avoid condensation

Additional insulation

Avoid thermal bridges

Airtightness!

Slits in the concrete slab to avoidnoise between apartments. Needs to be air tight !

Plasticfoil in corners

Double climate shell

Holes cloesely sealed!

Boklidens Vårdboende

Postiljonsgatan 10

Mörarp